The number 42945
42945 is a composite number with 16 divisors. Its prime factorisation is 3 × 5 × 7 × 409. Divisors (16): 1, 3, 5, 7, 15, 21, 35, 105, 409, 1227, 2045, 2863, 6135, 8589, 14315, 42945.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
42945 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
42945 is composite. Its prime factorisation is
- 3
The divisors add up to 78720; without 42945 itself that is 35775, so 42945 is deficient (35775 is less than 42945). Euler's totient φ(42945) = 19584 numbers up to 42945 share no factor with it.
- 4
The digits of 42945 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 75 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42945 = 3 \times 5 \times 7 \times 409 \]
42945 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 78720 |
| Euler totient φ(n) | 19584 |
| Square | 1844273025 |
| Cube | 79202305058625 |
| Square root | 207.231754 |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 75 |
| Scientific notation | 4.2945 × |
42945 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand nine hundred and forty-five |
| Binary (base 2) | 1010011111000001 |
| Octal (base 8) | 123701 |
| Hexadecimal (base 16) | A7C1 |
| Base 3 | 2011220120 |
| As time | 42945 seconds = 11 h 55 min 45 s |
Is 42945 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (42945 ÷ 3 = 14315) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (42945 ÷ 5 = 8589) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (42945 ÷ 7 = 6135) | A number is divisible by 7 if double the last digit and subtract it from the rest: the result is a multiple of 7. |
| 8 | No (remainder 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 6) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42945 a prime number?
No. 42945 = 3 × 5 × 7 × 409, so it is divisible by 3.
What are the factors of 42945?
1, 3, 5, 7, 15, 21, 35, 105, 409, 1227, 2045, 2863, 6135, 8589, 14315, 42945.
What is 42945 in binary?
1010011111000001 (hexadecimal A7C1, octal 123701).
What is the square root of 42945?
About 207.2318.
Is 42945 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 42945?
It is a composite number with 16 divisors.